Credit

Caption

Frozen storage of sperm and eggs. Small coloured tubes containing sperm and fertilized eggs (embryo's) are seen in frozen (cryogenic) storage. The blue container from which they are being removed is filled with liquid nitrogen, enabling low-temperature freezing typically to about -180 Celsius. The cells are frozen in a protective fluid to allow long-term storage without damage. When restored to normal temperature, the sperm may be used to fertilise other eggs or the embryo's may be allowed to grow into "test-tube" babies. This is the basis of IVF (in-vitro fertilisation), a technique used in couples who, for some reason, are unable to conceive normally.